Background. There are multiple documented advantages of undertaking total knee arthroplasty (TKA) without tourniquet, however, increased rates of blood loss and transfusion are often cited as contraindications to this approach. The aim of this study was to examine the effect of intra-operative TA administration on blood loss and transfusion rates in TKA without pneumatic tourniquet, using Rivaroxaban as thrombo-embolic prophylaxis. Method. 120 patients split into two continuous data sets, (A+B), underwent TKA without application of above knee tourniquet, receiving a post operative dose of oral Rivaroxaban within 8 hours. Group B patients received an intra-operative dose of 1 gram of Tranexamic Acid intravenously before the first cut, whilst those in group A did not. Haemoglobin and haematocrit levels were recorded peri-operatively. A revised Gross formula was used to calculate blood loss. Four patients were excluded from the study for incomplete data. Results. 58 patients (M34F24) in Group A, average age 6, had a mean haemoglobin drop of 33gram/litre, haematocrit drop of 0.097litre/litre (9.7%), with an average calculated blood loss of 1393ml. 58 (M34, F24) patients in group B, average age 67, had a haemoglobin drop of 25.2gram/litre, haemotocrit drop of 0.076litre/litre (7.6%) with an average calculated blood loss of1079ml. Thus Group A patients were seen to sustain significantly more blood loss without TA administration, with a 29.1% larger calculated blood loss, a 25.5% larger drop in haemoglobin and a 27.6% larger fall in haematocrit.
